Boring bar having internal coolant supply and cutter retaining nozzle

ABSTRACT

A boring bar has a shank having a cutter support head at one end. A flow passage extends longitudinally through the shank to the cutter support head and intersects a transverse flow passage that is defined in part by a clamp screw passage of the head. A metal cutting insert is clamped to the cutter support head by a clamp that is secured by a clamp screw being threaded into the clamp screw passage. The clamp member defines at least one coolant fluid flow passage having a discharge opening or openings each located and oriented to direct a jet of coolant fluid onto the metal cutting insert immediately at the site of cutting engagement within the rotating workpiece. The clamp screw defines an internal passage that communicates with the transverse coolant fluid flow passage and conducts coolant fluid onto the metal cutting insert. Alternatively, an annular clearance is defined about the shank of the clamp screw and serves as a coolant flow passage which is in fluid communication with the internal coolant fluid discharge passage or passages of the clamp member.

This is a Continuation-in-Part application based on pending applicationSer. No. ______ which was filed on Dec. 29, 2004 by Enrico R. Giannettiand is entitled “Boring Bar Having Internal Coolant Supply”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to machine tool holders such asboring bars that are mounted to machine tools and are used for externalmachining operations or for boring internal surfaces in work pieces thatare typically rotated by a machine tool. More particularly the presentinvention pertains to machine tool holders such as boring bars having aninternal coolant supply to discharge a liquid coolant and cutting fluidmedium immediately at the site of metal cutting by a metal cuttinginsert of a machine tool holder. Even more specifically, a coolant fluiddistributing nozzle also functions as a clamp for releasably securing ametal cutting insert to the cutter support head of a boring bar or othermachine tool holder.

2. Description of the Prior Art

A machine tool holder having a coolant fluid distribution system isshown in U.S. Pat. No. 6,652,200 of Kraemer. In this case, a platemember 30 is secured to a tool head and has multiple grooves that definecoolant passages and with discharge openings arranged to project streamsor jets of coolant fluid toward a machining interface. A coolant fluidsupply passage is defined within the head of the tool and receivescoolant fluid via a supply line having a connector that is attached tothe bottom part of the tool head.

During metal cutting operations, especially when heavy cuts of metal aretaken during rough metal cutting operations or when a hard metal isbeing machined, it is typical for the metal cutting machine to beprovided with a coolant fluid conduit through which a coolant and metalcutting fluid medium is pumped to the site of metal cutting. Typically,a fluid supply conduit, such as a flexible coolant supply hose incommunication with the discharge of a coolant supply pump, is providedwhich can be selectively oriented for delivery of the flowing coolantfluid medium to the cutter insert of the machine tool. The continuoussupply of coolant fluid to the metal cutting site minimizes heatbuild-up at the metal cutting site and thus maintains lower working orcutting temperature of the metal cutting element and ensures itsextended service life.

When metal cutting operations are carried out by a boring bar internallyof a rotating work-piece, such as is the case when boring operations arebeing carried out, the boring bar being used can have considerablelength, thus making it difficult to efficiently support a coolant supplytube or hose and conduct an adequate supply of coolant fluid to theimmediate region of the metal cutting insert of the boring bar. It isdesirable, therefore, to provide a metal boring tool system that doesnot require a coolant supply conduit to be supported along the length ofa boring bar and which ensures efficient and adequate delivery ofcoolant fluid to the immediate site of metal cutting for maintaining thecutting tool and the metal being cut within a predetermined temperaturerange. It is also desirable to provide a machine tool holder which, inaddition to the provision of one or more jets of coolant fluid forcooling of a machining interface, also provides one or more jets of chipflushing fluid from an internal coolant fluid supply which continuouslyflush away any accumulation of loose machining chips that mightotherwise interfere with efficient machining operations.

For application of a coolant medium to a metal cutting site, a spray ordistribution nozzle is typically mounted on or fixed to the cutting headof a cutter insert support machine tool. The spray or distributionnozzle defines one or more fluid flow passages that are in fluidcommunication with one or more coolant supply passages or lines. Thefluid discharge outlet or outlets of the spray or distribution nozzleare arranged to direct one or more jets of coolant fluid onto the cutterinsert of the tool so as to impinge at the point of cutter engagementwith the rotating work-piece. In the case of some machine tools ofconsiderable length, such as boring bar tools, it is difficult to mountcoolant supply tubes to the tools; thus adequate cooling of cutterinserts is not efficiently achieved. It is desirable therefore toprovide a machine tool having an internal coolant supply passage andhaving a coolant distribution nozzle that provides a jet or spray ofcoolant fluid at the immediate site of metal cutting regardless of thelength of the machine tool.

Positioning coolant supply tubes on or near cutting tools often obscuresthe metal cutting site to the point that visual inspection of the metalcutting operation is impaired. Also, the use of mounts to provideclamping or retaining support for replaceable metal cutting inserts andadditional mounts to support one or more coolant nozzles on machinetools typically makes the machine tools quite complex and expensive. Itis desirable therefore, to provide a machine tool having a singlemounting or retaining mechanism for securing a replaceable cutterelement to the head portion of the tool and for supporting a coolantdistribution nozzle that is positioned for application of coolant fluidto the immediate interface of metal cutting.

SUMMARY OF THE INVENTION

It is a principal feature of the present invention to provide a novelcutter insert support machine tool, such as a boring bar, having asingle mounting or retaining mechanism for securing a replaceable cutterelement to the head portion of the tool and for mounting a coolantdistribution nozzle that is positioned on the head portion of the toolfor application of coolant fluid to the immediate interface of the metalcutting insert with a rotating work-piece that is being machined.

It is another feature of the present invention to provide a novelmachine tool having a coolant supply passage therein and having acoolant supply nozzle in fluid communication with the coolant supplypassage and having one or more distribution openings located immediatelyadjacent the machining interface and wherein the coolant supply nozzleand its retainer bolt also serves a clamping function to secure areplaceable metal cutting insert to the head portion of the tool.

It is a principal feature of the present invention to provide a novelmachine tool, such as a boring bar, having one or more internal passagesfor flow of coolant and/or cutting fluid medium at least in the headportion thereof and having a metal cutting insert mount mechanismthereon that defines one or more fluid distribution passages directingthe flow of the coolant fluid medium to the immediate site of metalcutting by the replaceable cutter element of the machine tool;

It is another feature of the present invention to provide a novelmachine tool such as a boring bar having a fluid flow passage extendinglongitudinally therethrough and supplying a flow of coolant fluid to adistribution passage system of the cutter support head of the machinetool, which is oriented for delivery of coolant fluid to the point ofmetal cutting of a replaceable metal cutting insert that is mounted tothe head structure of the tool;

It is also a feature of the present invention to provide a novel machinetool such as a boring bar having a head structure to which a metalcutting insert is releasably fixed by a clamp assembly and with a clampmember of the clamp assembly defining a portion of a coolant fluidsupply passage and having a coolant fluid distribution opening that islocated to direct a jet of coolant fluid onto the metal cutting insertand at the immediate vicinity of metal cutting during a boringoperation; and

It is an even further feature of the present invention to provide anovel boring bar assembly wherein a clamp is secured to a machine toolhead by a clamp screw for supporting a replaceable metal cutting insertand wherein the clamp and clamp screw cooperate with the head structureof the machine tool to define one or more coolant fluid flow passageshaving at least one coolant fluid discharge opening on the clamp fordirecting one or more jets of coolant fluid to the immediate site ofmetal cutting.

Briefly, the various objects and features of the present invention arerealized through the provision of a machine tool such as a boring barhaving an elongate shank having an integral cutter support headstructure at one end. A coolant fluid flow passage extendslongitudinally through the shank of the machine tool to the cuttersupport head and intersects a transverse coolant fluid flow passagewhich is defined in part by a clamp screw passage. Alternatively, thecoolant fluid flow passage can be provided only in the head portion ofthe tool, with a coolant supply line of the tool being connected to thetool head. In accordance with the preferred embodiment and best mode ofthe present invention, a coolant distribution nozzle is mounted to thehead of the tool by a mounting bolt and the nozzle and its mounting boltprovide for coolant distribution to the metal cutting interface and alsoprovide a clamping function for retaining a metal cutting insert inproper position on the tool head for optimum machining. Alternatively, areplaceable metal cutting insert is clamped to the cutter support headstructure by a clamp member that is secured by a clamp screw beingthreaded into the clamp screw passage. The clamp screw, and itsassociation with the cutter support head structure, cooperate to definean internal or external flow passage permitting fluid flow transitionfrom the longitudinal boring bar flow passage and through the head andclamp structures. The clamp member defines one or more internal coolantfluid flow passages that terminate at one or more discharge openingslocated on the clamp member. The discharge opening or openings are eachlocated and oriented to direct a discharge or jet of coolant fluid ontothe metal cutting insert immediately at the site of its metal cuttingoperation within the rotating work-piece. In the preferred embodiment ofthe invention the clamp screw defines an internal passage that is incommunication with the transverse coolant fluid flow passage andconducts coolant fluid to the internal coolant fluid flow passage orpassages of the clamp member for precise distribution of coolant flow tothe metal cutting insert. In a further alternative embodiment of theinvention, an annular clearance is defined about the shank of the clampscrew and which serves as a flow passage. This annular flow passage isin fluid communication with the internal coolant fluid discharge passageor passages of the clamp or coolant fluid distribution nozzle member.The coolant fluid distributing nozzle defines an internal coolant flowpassage having an exit or discharge opening directed immediately at thesite of metal cutting by the insert and thus maintains the metal cuttinginsert as cool as possible during boring operations. The coolantminimizes heat induced wear and deterioration of the metal cuttinginsert and thus enhances its service life.

The cutter head of the machine tool holder of the present invention isalso machined to provide a coolant fluid distribution passage andopening that directs a jet of coolant fluid in a manner for flushingaway metal chips and preventing an accumulation of metal chips orcuttings that might otherwise interfere with the efficiency and accuracyof a metal cutting operation.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features, advantages andobjects of the present invention are attained and can be understood indetail, a more particular description of the invention, brieflysummarized above, may be had by reference to the preferred embodimentthereof which is illustrated in the appended drawings, which drawingsare incorporated as a part hereof.

It is to be noted however, that the appended drawings illustrate only atypical embodiment of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

In the Drawings:

FIG. 1 is a plan view of a machine tool holder such as a boring barhaving coolant fluid supply passages therein according to the principlesof the present invention, and representing an embodiment of theinvention;

FIG. 2 is a side elevational view of the machine tool holder of FIG. 1;

FIG. 3 is a rear elevational view of the machine tool holder of FIG. 1,showing a coolant flow passage longitudinally within the shank of themachine tool holder with the inlet of the coolant flow passage beinginternally threaded for attachment of the connector of a coolant supplyconduit to the machine tool holder;

FIG. 4 is a longitudinal sectional view of the machine tool holder ofFIGS. 1-3, showing an internal longitudinal coolant flow passage throughthe shank and showing a cutter support head and clamp assembly havingmetal cutting insert being secured in assembly therewith and having acoolant supply passage extending from the internal longitudinal coolantflow passage to a coolant discharge opening directed at the metalcutting insert;

FIG. 5 is an exploded isometric illustration of the machine tool holderof FIGS. 1-5;

FIG. 6 is a plan view of the integral shank and head structure of themachine tool holder of FIGS. 1-5 and showing the internal coolant flowpassage thereof in broken line;

FIG. 7 is a side elevational view of the integral shank and headstructure of the machine tool holder of FIG. 6, showing coolant flowpassage and cutter mounting receptacles in broken line;

FIG. 8 is a rear elevational view of the machine tool holder of FIGS. 6and 7, showing the coolant entry opening and connector receptacle of thelongitudinal flow passage and the cutter insert mounting receptacles inbroken line;

FIG. 9 is a sectional view of a clamp member for retaining cuttinginserts in assembly with the integral shank and head structure of themachine tool holder of FIGS. 4-6;

FIG. 10 is a bottom view of the clamp member of FIG. 9;

FIG. 11 is a front elevational view of the clamp member of FIGS. 9 and10;

FIG. 12 is an elevational view of a clamp screw member for retention ofthe clamp member in secure assembly with the head structure of themachine tool holder and having broken lines showing a longitudinalcoolant flow passage extending therethrough;

FIG. 13 is an elevational view of the clamp screw being offset 90° fromthe position of FIG. 12 and showing a transverse coolant flow passage incommunication with the longitudinal coolant flow passage of the shank ofthe machine tool holder;

FIG. 14 is an elevational view of a seat screw that is employed forretention of a seat member in assembly with the head structure of themachine tool holder;

FIG. 15 is a plan view of the seat screw of FIG. 14; and

FIG. 16 is a partial longitudinal sectional view showing a boring barrepresenting an alternative embodiment of the invention and havingcoolant fluid supply passages therein according to the principles of thepresent invention,

FIG. 17 is an isometric illustration in partially exploded manner,showing a machine tool holder, such as a boring bar, having a coolantfluid distribution system, and representing the preferred embodiment andbest mode of the present invention;

FIG. 18 is a plan view of the machine tool holder of FIG. 1;

FIG. 19 is a longitudinal sectional view of the machine tool holder ofFIGS. 1 and 2, the section being taken along lines 3-3 of FIG. 2;

FIGS. 20 and 20 a are exploded isometric illustrations showing the fluiddistribution and clamping nozzle components of the preferred embodimentand showing that clamping nozzles of different nozzle opening dimensionmay be employed depending upon the needs of any particular machiningoperation;

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

For purposes of simplicity, the present invention is discussed hereinparticularly with respect to its form as a boring bar for cutting orboring the interior of a rotating work-piece. However, it is to beunderstood that the present invention has application to a wide range ofmachine tool holders; thus this specification is to be intended asdescriptive of preferred embodiments of the invention and not asrestricting the spirit and scope of the invention. Also, while thecoolant medium is referred to as a fluid, it is intended that thecoolant fluid medium may comprise a liquid or liquid mixture or air orany suitable gaseous medium. Referring now to the drawings and first toFIGS. 1-3 a coolant fluid supplying machine tool holder such as a boringbar is shown generally at 10, having a coolant fluid flow passagetherein and representing a preferred embodiment of the presentinvention. The boring bar 10 comprises an elongate shank 12 having acoolant supplying cutter support head 14 integral therewith. As isevident from the longitudinal sectional view FIG. 4 a coolant fluid flowpassage 16 extends longitudinally through the elongate shank 12 to thecoolant supplying cutter support head 14 and is provided with aninternally threaded receptacle 18. The receptacle 18 is adapted toreceive a connector fitting 20 of a fluid supply conduit, such as aflexible coolant fluid supply hose that that is in fluid communicationwith the discharge passage of a coolant fluid supply pump of a boringmachine tool. The coolant fluid flow passage 16 intersects a transversecoolant fluid supply passage 22 that extends through the cutter supporthead 14 and defines an internally threaded receptacle 24 that is adaptedto receive a threaded closure plug member 26. If the internally threadedreceptacle 18 is closed by a similar threaded closure plug, thetransverse coolant fluid supply passage 22 will serve as an alternativecoolant fluid inlet passage, with the connector 20 of a coolant fluidsupply conduit being threaded into the internally threaded receptacle24. This feature provides machine operator personnel with a choice ofcoolant conduit connection that best suits the machining operation to beconducted.

A portion of the transverse coolant fluid supply passage 22 also servesas a screw passage and is internally threaded as shown at 28 to receivethe threaded shank 30 of a clamp screw 32. The clamp screw defines alongitudinal internal coolant fluid flow passage 34, as is evidentparticularly in FIGS. 4, 12 and 13, which is in fluid communication withthe transverse coolant fluid flow passage 22 and thus conducts coolantfluid flow from the passages 16 and 22 to a transverse screw passage 36which defines at least one and preferably a pair of opposed coolantfluid outlets 38 and 40. The clamp screw 32 defines a screw head 42having an annular downwardly facing retainer shoulder 44 which islocated immediately above an annular seal washer locator surface 46. Thescrew head 42, defines a screw actuator receptacle 48 which ispreferably in the form of a hex or Torx receptacle or may convenientlytake the form of a slotted or Phillips receptacle if desired. Whenthreaded to its full extent within the threaded section 28 of thetransverse coolant fluid supply passage 22, the annular downwardlyfacing retainer shoulder 44 is in retaining engagement with a sealwasher member 50 and forces the seal washer member into tightly seatedand sealed relation with an upper surface 52 of a clamp member 54, whichis shown in FIG. 4 and in greatest detail in FIGS. 9-11. Duringtightening movement of the clamp screw 32 by a hex or Torx wrench theannular seal washer locator surface 46 engages within a central opening56 of the seal washer member 50 and causes centering of the seal washermember with respect to the transverse coolant fluid supply passage 22.This feature ensures that the seal washer member establishes fluid tightsealing with the surface 52 entirely about a retainer screw opening 58of the retainer member 54. This feature also ensures against leakage ofthe coolant fluid medium from the retainer screw opening 58.

As is evident particularly in FIGS. 9 and 10, as well as FIGS. 4 and 5,the clamp member 54 defines a downwardly facing seal receptacle 60 thatis preferably concentric with the retainer screw opening and has anannular seal retainer shoulder 62. An annular seal member 64 is at leastpartially received within the downwardly facing seal receptacle 60 andis forced by the annular seal retainer shoulder 62 into sealedengagement with the clamp member 54 and with an upper surface 66 of theboring bar head structure 14. The annular seal member 64 may be composedof any suitable resilient or elastomeric sealing material or it may becomposed of any metal or non-metal material that is capable ofestablishing sealing between the clamp member and the head structure ofthe boring bar when the clamp screw 32 is tightened. The clamp member 54defines an internal slot 68 which is sealed at its upper end by the sealwasher member 50 and is in fluid communication with an annular groove orrecess 70 within which the coolant fluid outlet openings 38 and 40 arelocated. The clamp member also defines a coolant discharge passage 72extending from the internal slot 68 to a discharge opening 74. Ifdesired, the clamp member may define a plurality of coolant dischargepassages having a plurality of coolant discharge openings if additionalor more efficient cooling can be achieved. The coolant fluid dischargepassage 72 and the discharge opening 74 are oriented and located toproject a jet of coolant fluid strategically onto a metal cutting insert76 so that the cutting edge of the metal cutting insert and the metalbeing cut receive continuous cooling. The service life of the metalcutting insert and the efficiency of metal cutting is enhanced when thecutting temperature is controlled by an efficient and accuratelydirected and controlled flow of coolant immediately at the site of themetal cutting operation.

The clamp member 54 is located and stabilized in part by a downwardlyextending locator projection 78 which is of elongate configuration andis defined by oppositely inclined downwardly converging side camsurfaces 80 and 82 that intersect at an elongate rather sharp ridge 84.The downwardly extending locator projection 78 also defines oppositelyinclined downwardly converging end cam surfaces 86 and 88 that intersectthe ridge 84 and define the ends of the ridge. The downwardly extendinglocator projection 78 is received by a clamp location and stabilizingreceptacle 90 having a corresponding downwardly converging taperedconfiguration and permits the downwardly extending locator projection 78to establish substantial surface to surface locking and stabilizingengagement with the head structure 14 of the boring bar as indicatedparticularly in FIG. 4. This feature prevents movement of the clampmember 54 even when subjected to the forces of heavy or rough metalcutting by the replaceable metal cutting insert 76, especially duringthe initial stage of machining.

The clamp member 54 also defines a retainer nose portion 92 on which isintegrally formed a cutter insert locator projection 94 of generallycylindrical configuration. The cutter insert locator projection 94 isreceived within a central opening 96 of the cutter insert member 76 forprecision location of the replaceable cutter insert member 76 on thecoolant supplying cutter support head 14. When seated to its full extentthe lower end 98 of the cutter insert locator projection 94 is locatedin close fitting relation within the central opening 96 of the cutterinsert to ensure against shifting of the cutter insert even under theinfluence of the significant forces of rough metal cutting. The centralopening 96 is also of generally cylindrical configuration and thusensures against any lateral as well as vertical movement of the cutterelement relative to the clamp member 54.

The head structure 14 of the boring bar 10 is drilled or otherwiseformed to define a passage 102, as shown in FIG. 4, which includes aninternally threaded section 104 that receives the threaded shank 106 ofa seat screw 108, which is shown in greater detail in FIGS. 14 and 15.The seat screw 108 defines a screw actuator receptacle 110 which may beof hex or Torx form or may have any other screw actuator receptacle formas desired. The seat screw 108 also defines a screw head 112 having atapered shoulder surface 114 that establishes locating and stabilizingengagement within a central correspondingly tapered annular internalsurface 116 that defines at least a portion of a opening 117 of a seatmember 118. The seat screw is tightened to force the seat member 118into supported engagement with a seat support shoulder 120 of the headstructure 14. The seat support shoulder 120 is oriented at a desiredangle, with respect to the center-line of the boring bar shank 12, toachieve desired orientation of the seat member 118 and the metal cuttinginsert 76 for optimum metal cutting and extended service life of themetal cutting insert.

Generally planar seat locator and stabilizer surfaces 122 and 124 aredefined by the head structure 14 and are oriented for precision locationand stabilization of respective side surfaces 126 and 128 of thegenerally rectangular seat member 118. When the seat member is securedin place by the seat screw 108, the planar seat locator and stabilizersurfaces 122 and 124 prevent the seat member from being rotated orotherwise moved by the forces encountered during machining. Precisionlocation of the seat member 118 on the seat and cutter support shouldersurface 120 is controlled by interaction of the tapered shoulder surface114 of the seat screw 108 with the correspondingly tapered internalsurface that is defined within the seat member 118. Generally planarcutter insert locator surfaces 130 and 132 are also defined by the headstructure 14 and are oriented in angular relation for precision locationand support with corresponding side surfaces or edges 134 and 136 of thegenerally rectangular cutter insert 76. Support ledges 138 and 140 aredefined at the juncture of the seat locator and stabilizer surfaces 122and 124 and the cutter insert locator surfaces 130 and 132 to providesupport for respective lower edges of the metal cutting insert 76. Acorner relief recess 142 is also defined in the head structure 14 and isdefined in part by curved or arcuate corner relief recess surfaces 144and 146 at the juncture of the seat and cutter insert support andstabilization surfaces. The corner relief recess 142 ensures that acorner of the seat member 118 and metal cutting insert 76, are free fromcontact with the locating and stabilizing surfaces of the head structure14. The corner relief recess 142 is also defined in part by a curved orarcuate ledge 148 which exists due to the differing dimensions of thelocating and stabilizing surfaces of the head structure 14.

With reference to FIGS. 6-8, it should be borne in mind that thetransverse coolant fluid supply passage 22 may be drilled or otherwiseformed so that it does not extend completely through the head structure14 of the machine tool holder or boring bar 10. In such case, thepassage 22 merely extends a sufficient distance to establish fluid flowconducting communication with the longitudinal coolant fluid flowpassage 16 which is evident particularly as shown in broken line in FIG.7. The coolant fluid supply passages are arranged as shown in FIG. 4 ifit is intended to provide the user with the capability of selectivelyconnecting a coolant fluid supply conduit to the internally threadedreceptacle 18 of the shank 12 or to the internally threaded receptacle24 of the head structure 14. In either case, a threaded plug member isemployed as a closure for the unused internally threaded receptacle 18or 24.

As shown in the embodiment of FIG. 4 coolant fluid flow from thetransverse coolant fluid supply passage 22 to the coolant fluiddischarge passage 72 of the clamp member 54 occurs via a longitudinalcoolant fluid flow passage 34 of the clamp screw 32. It should be bornein mind that coolant fluid flow may also or alternatively occurexternally of the clamp screw. As shown in the alternative embodiment ofFIG. 16, the screw passage is enlarged to provide an annular clearanceexternally of the clamp screw which serves as an annular flow passagefor coolant flow. In this case, the clamp screw will not be providedwith an internal longitudinal flow passage. Like components of FIG. 16,as compared with FIG. 4, are shown by like reference numerals.

As shown in FIG. 16, the head structure 14 is machined to define a clampscrew passage section 150 having a dimension exceeding the externaldiameter of the shank 152 of a clamp screw 154, thus establishing anannular flow passage 156 that surrounds the shank of the clamp screw.This annular flow passage intersects the longitudinal coolant fluid flowpassage 16 of the boring bar shank 12 and thus permits the flow ofcoolant fluid from the shank of the boring bar, through the headstructure to the flow passages 72 of the clamp member 54. Unlike theclamp screw 32 of FIG. 4, the clamp screw 154 has a shank 152 that doesnot define an internal longitudinal flow passage. Rather, the flowpassage 156 is defined by an annular space that is cooperatively definedby the external surface of the clamp screw shank 152 and the enlargedinternal surface of the clamp screw passage section 150. The shank 152of the clamp screw also defines an annular space with the internalsurface of the passage 58 through the clamp member, which annular spaceis an extension or continuation of the annular flow passage 156. Theupper end of this annular space is closed and sealed by the seal washer50. The annular seal member 64 establishes sealing of the annular flowpassage at the lower portion of the clamp member 54 as explained above.The function of the embodiment of FIGS. 4 and 16 are essentially thesame, with the exception that fluid flow along the shank of the clampscrew differs. In each case, the flow of coolant fluid from thelongitudinal flow passage of the shank 12 of the boring bar 10 istransitioned through the head structure 14 to the clamp member 54 and isthen conducted through the clamp member to one or more dischargeopenings 72 that are located and oriented to direct the flow of coolantfluid directly onto the cutter insert 76 to the immediate region ofcontact of the cutter insert within the rotating work-piece.

Referring now to FIGS. 17-20 a preferred embodiment and best mode of thepresent invention is represented by a machine tool holder assembly showngenerally at 160 which may conveniently take the form of a boring bar orany other type of support for a replaceable metal cutter element. Themachine tool holder, especially when in the form of a boring bar,includes an elongate tool shank 162 which, as shown in FIG. 19, definesan internal longitudinal coolant fluid supply passage 164 through whichcoolant fluid is conducted to the head portion 166 of the tool. A fluidsupply fitting 168, such as the 90° swivel fitting of FIGS. 18 and 19 isthreaded into one end of the tool shank 162 and provides for connectionto a coolant supply line, not shown. Within the head portion 166 of themachine tool holder is located a coolant distribution passage 170 whichis in fluid communication with the internal longitudinal coolant fluidsupply passage 164. The passage 170 is disposed in angulatedintersecting relation with the passage 164 thus permit its outlet end tobe properly oriented for flushing away metal chips or cuttings thatoccur during machining operations. A chip flushing nozzle 172 isthreaded into an internally threaded outlet section of the passage 170and provides a nozzle outlet 174 that is of proper dimension to developa jet 176 of coolant fluid that is oriented to blast away metal chipsand to thus minimize the potential for any undesirable accumulation ofmetal chips that might otherwise interfere with or otherwise compromisethe efficiency of the metal cutting operation.

The head portion 166 of the tool holder is machined to define aninternally threaded bore 178 which receives a retainer screw 180 andsecures a cutter insert seat member 182 firmly to a seat surface 184that is defined by the head portion 166 of the machine tool holder 160.The retainer screw is provided with a tapered head that is receivedwithin a screw head receptacle 188 of the seat member 182. When theretainer screw 180 is threaded into the threaded bore to its fullextent, the upper end of the retainer screw is recessed below the levelof the upper surface of the cutter insert seat member 182.

The head portion 166 of the tool holder is also machined to define aninternally threaded bore 190 that intersects the coolant distributionpassage 170 and receives a threaded retainer or clamp screw 192 thatsecures a combination nozzle and clamp member 194 to the head portion166. The combination nozzle and clamp member 194 bears against an uppersurface of a replaceable cutter element 196 and serves to retain thecutter element firmly seated on the seat member 182 and firmly securedwithin a cutter receptacle 198 of the tool head portion 166. The clampor retainer screw 192 defines an axial flow passage 200, shown in FIGS.19 and 20, that is in fluid communication with the coolant distributionpassage 170 and also defines a reduced diameter annulus 202 and a flowport 204 establishing communication of the annulus with the axialpassage 200. Leakage of coolant fluid at the retainer or clamp screw isprevented by a metal to metal seal that is developed by the flat annulardownwardly facing surface 203 of the screw head which engages acorresponding annular flat shoulder surface 205 that is located withinthe threaded receptacle 208. An annular resilient seal member 207 ispositioned around the threaded shank of the retainer bolt and iscompressed within an annular seal receptacle that is defined by thelower portion of the nozzle and clamp structure immediately about thescrew hole.

The combination nozzle and clamp member 194 defines one or more internalflow passages 206 that are in communication with a threaded receptacle208 within which the annulus 202 is received. The annulus communicatescoolant fluid from the axial flow passage 200 of the retainer bolt tothe passage or passages 206 and the passages direct the flowing coolantmedium to a discharge or jet opening 210 from which a jet or jets ofcoolant fluid is directed to the cutting interface which is located onlya few millimeters distant. As is indicated in FIG. 20 a, combinationnozzle and clamp members will be provided with discharge openings 210 aof differing dimension, depending on the volume of coolant fluid that isintended to be projected at the cutting interface. The jet or jets ofcoolant fluid are projected immediately to the typically small roundedcutting edge which is located at each of the typically two, three orfour corners of a replaceable metal cutting insert. Thus, a cutterinsert is typically loosened, rotated to another of its two, three orfour positions when one of its cutting edges becomes dull. This isrepeated until each of the cutting edges has been used to the point thatcutting efficiency has become degraded, after which the cutter insertelement is typically discarded and replaced by a new cutter insert.

At the juncture of the head portion 166 with the shank 162 there ismachined a depression 212 having an inclined surface 213. The rearportion of the combination nozzle and clamp member 194 defines adepending orienting and locking member 214 which fits within thedepression 212 with a tapered surface 216 disposed in orientingengagement with the inclined surface of the depression. This featurecontrols orientation of the nozzle member 194 so that the dischargeopening 210 is precisely oriented. Orientation of the nozzle member andprevention of its rotation during machining operations is furtherenhanced by a locking pin 211 which is received within a matching recessdefined by the rear portion of the nozzle member and with one end of thelocking pin being received within a vertically oriented hole of the headportion of the tool holder. Further, the inclined and tapered surfacesinteract during tightening of the retainer bolt 180 and cause thedevelopment of a generally horizontal pulling force which urges thecutter insert in a rearward direction thus ensuring that the cutterinsert is seated firmly against the angulated support surfaces or walls217 and 219 that define the cutting insert receptacle of the headportion of the tool holder. Also, the geometry of the nozzle and clampmember and the head portion of the machine tool holder cause the forwardend of the nozzle member 194 to apply a downwardly directed clampingforce to a cutter insert 196, thus positively retaining the cutterinsert in a manner preventing upward or downward movement or yieldingduring metal cutting operations.

At the forward end of the nozzle member 194 is located a dependinglocking member 218 which is received in close fitting relation within acircular retainer opening 220 which is located at the center of a cutterinsert. The locking member provides mechanical stabilization for thecutter insert during machining operations to prevent any degree ofrotation of the cutter insert within its seat while the clamping forceof the nozzle structure efficiently secures the cutter insert fromupward or downward movement.

In view of the foregoing it is evident that the present invention is onewell adapted to attain all of the objects and features hereinabove setforth, together with other objects and features which are inherent inthe apparatus disclosed herein.

As will be readily apparent to those skilled in the art, the presentinvention may easily be produced in other specific forms withoutdeparting from its spirit or essential characteristics. The presentembodiment is, therefore, to be considered as merely illustrative andnot restrictive, the scope of the invention being indicated by theclaims rather than the foregoing description, and all changes which comewithin the meaning and range of equivalence of the claims are thereforeintended to be embraced therein.

1. A coolant fluid supplying machine tool holder, comprising: anelongate shank member having an integral cutter support head at one endthereof; said integral cutter support head defining a cutter insertsupport seat and having a coolant fluid distribution passage therein; acoolant fluid nozzle and clamp member being retained in assembly withsaid integral cutter support head and securing a metal cutting insert incutting position on said cutter insert support seat, said coolant fluidnozzle and clamp member defining at least one internal fluid flowpassage in communication with said coolant fluid distribution passageand having at least one discharge outlet opening being oriented todirect at least one discharge jet of coolant fluid onto a machininginterface a metal cutting insert, and said internal fluid flow passageof said coolant fluid nozzle and clamp member being in fluidcommunication with said coolant fluid distribution passage.
 2. Thecoolant fluid supplying machine tool holder of claim 1, comprising: aretainer member securing said coolant fluid nozzle and clamp member tosaid cutter support head and defining fluid communication of saidcoolant fluid distribution passage of said cutter support head and saidinternal coolant flow passage of said coolant fluid nozzle and clampmember.
 3. The coolant fluid supplying machine tool holder of claim 1,comprising: said elongate shank member having longitudinal internalcoolant supply passage therein defining a fluid inlet opening; a coolantfluid distribution passage being defined at least partially in saidcutter support head and having fluid communication with saidlongitudinal internal coolant supply passage; and a retainer membersecuring said coolant fluid nozzle and clamp member to said cuttersupport head and defining fluid communication of said coolant fluiddistribution passage of said cutter support head and said internalcoolant fluid flow passage of said nozzle and clamp member.
 4. Thecoolant fluid supplying machine tool holder of claim 1, comprising: aretainer member securing said nozzle and clamp member in releasableassembly with said cutter support head; and a coolant fluid passagebeing defined internally of said retainer member and establishing fluidcommunication of said coolant fluid distribution passage of said cuttersupport head with said internal coolant flow passage of said nozzle andclamp member and said internal fluid flow passage of said nozzle andclamp member.
 5. The coolant fluid supplying machine tool holder ofclaim 1, comprising: a clamp screw receptacle being defined in saidcutter support head and having fluid communication with said internalcoolant fluid distribution passage and with said internal clamp fluidflow passage, said clamp screw receptacle having an internally threadedsection; and a clamp retainer screw having a screw shank defining anexternally threaded section being threaded into said internally threadedsection of said clamp screw receptacle, said screw shank defining aninternal fluid passage in communication with said coolant fluiddistribution passage and in communication with said internal fluid flowpassage of said nozzle and clamp member.
 6. The coolant fluid supplyingmachine tool holder of claim 1, comprising: a cutter insert receptaclebeing defined by said cutter support head and having cutter supportshoulders; an inclined surface being defined by said cutter supporthead; a locking member depending from said nozzle and clamp member forengagement within an opening of a replaceable cutter insert; a retainerscrew securing said nozzle, and clamp member to said cutter supporthead; and said nozzle and clamp member defining a tapered surface havingengagement with said inclined surface and upon tightening of saidretainer screw member developing a pulling force causing said lockingmember to secure a replaceable cutter insert against said cutter supportshoulders.
 7. The coolant fluid supplying machine tool holder of claim1, comprising: a clamp screw receptacle being defined in said cuttersupport head and having fluid communication with said internal coolantfluid flow passage and with said internal clamp fluid flow passage, saidclamp screw receptacle having an internally threaded section; and aclamp retainer screw having a screw shank defining an externallythreaded section being threaded into said internally threaded section ofsaid transverse coolant fluid flow passage, said clamp retainer screwshank having annular clearance within said cutter support head definingan internal annular fluid passage externally of said screw shank andbeing in communication with said coolant fluid distribution passage ofsaid cutter support head, said annular fluid passage also being in fluidcommunication with said internal fluid flow passage of said nozzle andclamp member.
 8. The coolant fluid supplying machine tool holder ofclaim 1, comprising: a coolant fluid distribution passage being definedin said cutter support head and having fluid communication with saidinternal coolant fluid supply passage and with said internal fluid flowpassage of said nozzle and clamp member, said internal coolant fluidsupply passage having a fluid inlet opening and defining a threadedreceptacle at said coolant inlet opening, a threaded connector of acoolant fluid supply conduit having threaded engagement within saidthreaded receptacle; and a chip flush nozzle being mounted to saidcutter support head and being in fluid communication with said coolantfluid distribution passage and directing a jet of coolant fluid to alocation for removal of machine chips from a machining interface duringmachining operations.
 9. The coolant fluid supplying boring bar of claim1, comprising: a clamp retainer screw member extending through saidnozzle and clamp member and into said cutter support head and retainingsaid nozzle and clamp member in releasable cutter insert clampingassembly with said cutter support head; a first seal member sealing saidclamp retainer member with respect to said nozzle and clamp member andpreventing leakage of coolant fluid; and a second seal member sealingsaid nozzle and clamp member with respect to said cutter support head.10. A coolant fluid supplying machine tool holder, comprising: anelongate shank member having an integral cutter support head at one endthereof and defining an internal coolant fluid supply passage extendingwithin said elongate shank member and within said integral cuttersupport head; a cutter support seat being defined by said integralcutter support head; a nozzle and clamp member being releasably seatedon said integral cutter support head and securing a metal cutting insertin cutting position on said cutter support seat, said nozzle and clampmember defining at least one internal fluid flow passage having at leastone discharge outlet opening being located and oriented to direct atleast one jet of coolant fluid from said internal fluid flow passageonto a metal cutting insert, and a clamp retainer screw extendingthrough said nozzle and clamp member and being threaded into said cuttersupport head and securing said nozzle and clamp member in releasableclamping engagement with said cutter support head and with a metalcutting insert, said clamp retainer screw and said cutter support headdefining a flow passage in communication with said internal coolantfluid flow passage and with said internal coolant fluid supply passage.11. The coolant fluid supplying machine tool holder of claim 10,comprising: a coolant fluid passage being defined internally of saidclamp retainer screw and having fluid communication with said internalcoolant fluid flow passage of said nozzle and clamp member and with saidinternal coolant fluid supply passage of said elongate shank member. 12.The coolant fluid supplying machine tool holder of claim 10, comprising:a coolant fluid passage being defined externally of said clamp retainerscrew and having fluid communication with said internal coolant fluidflow passage and with said internal coolant fluid supply passage. 13.The coolant fluid supplying machine tool holder of claim 10, comprising:said elongate shank member having a fluid inlet end having a fluid inletopening and defining a threaded receptacle at said coolant inletopening, said threaded receptacle receiving a threaded connector of acoolant fluid supply conduit.
 14. The coolant fluid supplying machinetool holder of claim 10, comprising: a coolant fluid distributionpassage being defined at least partially in said cutter support head andhaving fluid communication with said internal coolant fluid flow passageand with said internal coolant fluid supply passage.
 15. The coolantfluid supplying machine tool holder of claim 10, comprising: a clampscrew receptacle being defined in said cutter support head and havingfluid communication with said internal coolant fluid flow passage andwith said internal clamp fluid flow passage, said clamp screw receptaclehaving an internally threaded section; and said clamp retainer screwhaving a screw shank defining an externally threaded section beingthreaded into said internally threaded section of said transversecoolant fluid flow passage, said screw shank defining an internal fluidpassage in communication with said coolant fluid distribution passageand having an outlet in communication with said internal fluid flowpassage of said nozzle and clamp member.
 16. The coolant fluid supplyingmachine tool holder of claim 10, comprising: a clamp screw receptaclebeing defined in said cutter support head and having fluid communicationwith said internal coolant fluid distribution passage and with saidinternal fluid flow passage of said nozzle and clamp member said clampscrew receptacle having an internally threaded section; said clampretainer screw having a screw shank defining an externally threadedsection being threaded into said internally threaded section of saidtransverse coolant fluid flow passage, said clamp retainer screw shankhaving annular clearance within said cutter support head defining aninternal annular fluid passage externally of said screw shank and beingin communication with said coolant fluid distribution passage, saidannular fluid passage also being in fluid communication with saidinternal coolant fluid flow passage; and a chip flush member beingmounted to said cutter support head and being in communication with saidinternal coolant fluid distribution passage, said chip flush memberdefining a discharge opening from which a jet of coolant fluid isprojected for flushing machining chips from a machining interface with awork-piece.
 17. The coolant fluid supplying machine tool holder of claim10, comprising: a coolant fluid distribution passage being defined insaid cutter support head and having fluid communication with saidinternal coolant fluid supply passage and with said internal coolantfluid flow passage, said coolant fluid supply passage having a fluidinlet opening and defining a threaded receptacle at said coolant inletopening, and a threaded connector of a coolant fluid supply conduithaving threaded engagement within said threaded receptacle.
 18. Thecoolant fluid supplying machine tool holder of claim 10, comprising: aclamp retainer screw extending through said clamp member and into saidcutter support head and retaining said clamp member in releasableassembly with said cutter support head; a first seal member sealing saidclamp retainer member with respect to said nozzle and clamp member andpreventing leakage of coolant fluid; and a second seal member sealingsaid nozzle and clamp member with respect to said cutter support head.19. A coolant fluid supplying machine tool holder, comprising: anelongate shank member having an integral cutter support head at one endthereof and defining an internal coolant fluid supply passage extendingwithin said elongate shank member, said internal coolant fluid supplypassage having a coolant inlet opening and an internally threadedreceptacle; said integral cutter support head defining a cutter supportseat and defining a fluid distribution passage being in communicationwith said internal coolant fluid supply passage; a nozzle and clampmember being releasably seated on said integral cutter support head forclamping retention of a metal cutting insert in cutting position on saidcutter support seat, said nozzle and clamp member defining at least oneinternal coolant fluid flow passage having at least one discharge outletopening being oriented to direct a discharge of coolant fluid from saidinternal coolant fluid flow passage onto a metal cutting insertimmediately at a machining interface with a rotating work-piece, saidinternal coolant fluid flow passage being in fluid communication withsaid fluid distribution passage; and a clamp retainer screw extendingthrough said nozzle and clamp member and being threaded into said cuttersupport head and securing said nozzle and clamp member in releasableclamping engagement with said cutter support head and with a metalcutting insert, said clamp retainer screw and said cutter support headdefining a flow passage in communication with said internal coolantfluid distribution passage and with said internal clamp fluid flowpassage.
 20. The coolant fluid supplying machine tool holder of claim19, comprising: said cutter support seat of said integral cutter supporthead having cutter support shoulders; said integral cutter support headdefining a recess having an inclined surface; said nozzle and clampmember defining a locking projection for engagement within an opening ofa cutter insert and further defining a locking member having a taperedsurface; and during tightening of said clamp retainer screw saidinclined surface and said tapered surface engaging and developing apulling force pulling said locking member and forcing a cutter inserttightly against said cutter support shoulders.